4
questions

last week new tune up (plugs / wires), new air and fuel filter, new fuel regulator
when i turn on key fuel gauge goes to 55 psi and then drops to 0 psi, but when i turn key the rest of the way to start it starts (sometime i crank for 3 sec and stop then start cranking and it starts) then fuel pressure is 48 psi and fluxuates a little when giving it gas

it could be a security anti theft problem, also put in a new key and ignition

This problem is intermittent

truck has new starter , new battery , all fuses have been checked, but when trying to start vehicle nothing happens , lights on dash come on but engine doesnt do anything, what other things can i check for or what might be the issue